【目的】探明秸秆还田和氮肥管理对麦/油后直播杂交稻氮素积累、转运、氮肥利用效率及籽粒产量的影响。【方法】选用优质三系杂交稻宜香优2115,采用二因素裂区设计,麦、油茬田同步开展试验,处理完全一致。主区为麦/油秸秆全量翻埋还田(M₁)和秸秆不还田(对照,M₀),副区设4个氮肥管理,即不施氮对照(N₀)、m_基肥∶m_分蘖肥∶m_促花肥∶m_保花肥比例分别为1∶0∶0∶0(N₁)、3∶3∶2∶2(N₂)、2∶2∶3∶3(N₃),测定了直播杂交稻主要生育时期各器官的氮素积累量及籽粒产量。【结果】结果表明,两种轮作方式下,氮肥管理对直播杂交稻主要生育时期的氮素积累、齐穗后茎鞘、叶片的氮素转运及稻株氮素利用效率均存在显著或极显著的调控效应。秸秆还田显著提高麦/油茬杂交稻中后期的氮素积累量、茎鞘和叶片的氮素转运量以及氮肥利用效率,其中,氮肥农学利用率、氮肥偏生产力和氮肥表观利用率较秸秆不还田分别提高了34.96%/28.76%、2.52%/2.61%和31.91%/22.30%。同时,油菜秸秆还田下直播杂交稻各生育时期氮素积累和产量较麦秆还田表现更好,籽粒产量提高481 kg/hm²(5.22%)。M₁N₂处理、M₀N₃处理下,直播杂交稻各阶段的氮素积累速率明显加大,促进结实期茎鞘和叶片的氮素向穗部转运,成熟期稻株氮素积累量优势明显且有较高的氮素利用效率(麦/油茬稻氮肥农学利用率、偏生产力和表观利用率分别达17.87 kg∙kg^-1/17.85 kg∙kg^-1、67.27 kg∙kg^-1/71.28 kg∙kg^-1、74.93%/75.05%),最终实现高产。【结论】在麦/油-稻轮作下秸秆全量还田,配合N₂氮肥管理,可有效提高直播杂交稻氮素吸收、利用效率,增加籽粒产量,尤以油菜秸杆还田的效果更好。

【Objective】It is very impontant to reveal the effects of straw returning and nitrogen fertilizer management on nitrogen accumulation, transport, nitrogen use efficiency and grain yield of direct seeded hybrid rice under wheat/rape-rice rotation.【Methods】A two-factor split zone design was adopted with Yixiangyou 2115, three-line hybrid rice with high quality, as material. The experiment was carried out simultaneously in paddy fields with wheat or rape stubble. The treatment was completely the same. The main area was wheat /rape straw returning to the field (M₁) and zero straw returning(M₀), with sub-plot of four nitrogen fertilizer managements: zero nitrogen control(N₀), basal fertilizer: fertilizer for tillering: fertilizer for flower promotion: fertilizer for flower preservation=1:0:0:0(N₁), 3:3:2:2(N₂), 2:2:3:3(N₃), respectively. The nitrogen accumulation of each organ of main growth stage of direct seeded hybrid rice were measured, as well as grain yield.【Results】The results showed that under the two rotation methods, nitrogen fertilizer management had significant or highly significant regulatory effects on nitrogen accumulation in main growth stage, nitrogen transportation of stem, sheath, leaves after full heading and nitrogen use efficiency of direct seeded hybrid rice. Straw returning significantly increased nitrogen accumulation, nitrogen transport of stem, sheath, leaves and nitrogen use efficiency in the middle and late stages of hybrid rice with wheat /rape stubble manuring. The agronomic use efficiency, partial productivity and apparent utilization efficiency of nitrogen fertilizer increased by 34.96%/28.76%, 2.52%/2.61% and 31.91%/22.30%, respectively. Meanwhile. the nitrogen accumulation at various growth stage and yield of direct seeded hybrid rice with rape straw returning were better than those of wheat straw returning, and the grain yield increased by 481 kg/hm²(5.22%). It could effectively increase the rate of nitrogen accumulation in each stage of direct seeded hybrid rice, promote the transportation of nitrogen from stem, sheath and leaves to panicle in productive stage and nitrogen accumulation amount of rice plant at mature stage had obvious advantage and high nitrogen use efficiency (nitrogen agronomic use efficiency, partial productivity and apparent nitrogen use efficiency in paddy field with wheat / rape stubble returning reached 17.87 kg∙kg^-1/17.85 kg∙kg^-1, 67.27 kg∙kg^-1/71.28 kg∙kg^-1, 74.93%/75.05%) under M₁N₂, M₀N₃.【Conclusion】Under M₁N₂ the nitrogen absorption and utilization efficiency together with the grain yield were effectively improved, rape straw returning in particular.